Smoky Volvo

[harstonwood]

Boatmike, Reading this thread, volvopaul has given you lots of (free) advice
I would listen (read) to his advice carefully, as there is absolutely no doubt in my mind, having read his posts, and met Paul, that he is an absolute guru on all matters Volvo. Like me he is from up North, so can be forthright in his views. To me that is a good thing.

To get advice of this quality is fantastic.

Cheers

 

[volvopaul]

Im surprised to hear your 41P prefix engine smokes as it was the last of the run and a very smoke free friendly engine when new.

Id say you havea problem somewhere, but to diagnose it via this forum is like playing pin the donkeys tail!

You must check the obvious and be sure the colour of smoke is related to the fault you think it is, white/grey is unburned fuel when not under load, are you sure its not steam?

Id start with injectors, then pump timing, then pump diagnosis, comp tests, valve clearances and a blow by test hich will indicate worn bores and valves that dont seat.

A blow by test can b carried out relatively cheaply by buying a small air compressor and rigging up some tool to sit where the injectors should be, you will of course have to rotate the engine so that each cylinder is on compression, ie both valves closed.

Id check the intercooler for large deposits of oil , maybe you have a turbo oil leak.

If you have sea water entering the engine via the CAC then that shows like smoke from the exhaust.

Come back to us.

Sarcasm eh???

 

[boatmike]

After a previous post which was a joke (boatmike) I will bother to help you as no doubt it will help others on here too.

The 41s problems is all relative to use and age, along with how its been looked after over its life, you would never see 40,000 hours from a 41 let alone many other leisure rated marine engines.

Id start with a full service, change oil, fuel air breather filters and impellers, belts, anodes if it has them you may find one in the heat exchanger and oil cooler, coolant, gearbox oil.

Make a general inspection of the mounts as you have a heavy boat, the vertical posts break, there is a mod available to fit larger diameter posts and new rubber mounts.

Check the valve clearances, and maybe remove the injectors for testing as 41s dont have the best bosch injectors out there, ive fitted hundreds over the years and believe me outright new ones make a big difference to a 41.

Hope that helps you out boatmike, this forum can be really good you know.

Paul, I have been contributing to this forum for a long time. It is indeed an excellent place to exchange information. I tend to ignore any controversy regarding literary style and explained my position in some detail to explain why I was not up to speed with this particular engine. I was obviously aware that it was a turbo but not that it was aftercooled and your terminology was not recognised. When I don't know something I ask. There is no shame in not knowing and if you don't ask you won't learn.
Of course I will do the obvious things you mention which I would do on any engine, turbo, or naturally aspirated, with or without inter or aftercooling.
I will indeed also check the engine mounts carefully. Thank you for that tip which I appreciate.
Yes I have also been told to watch out for injectors and will probably pull them and get them checked out for spray pattern etc. at a local fuel system repair shop. This much I am very familiar with as I served my original time with CAV back in 1956! What I am still not sure about is the aftercooler configuration. I assume it is watercooled and perhaps from your comments raw watercooled rather than on the freshwater circuit? If so this would, if there were a leak cause steam in the exhaust which might be mistaken for smoke. Is that what you were intimating or have I yet again misunderstood you? Your previous post aimed at the original question didn't explain this side of things in any detail and was not in reply to my question but a previous one.
While we are on the subject, do you agree that this solenoid actuated exhaust choke was only on this engine and dropped on subsequent marques being unnecessary due to upping the CR on later ones? If so what are your thoughts about the additives that are supposed to raise the cetane rating of the fuel. One previous poster said it helped but as my engines only seem to smoke when cold I am inclined to accept it as normal. There is no smoke or steam when hot regardless of throttle setting. By the way my hours counter says they have done 750 hours and I agree 40,000 would be an exceptional life.

 

[volvopaul]

Hi mike, the raw water circuit which does cooler the aftercooler is fed from the sea water pump, water enters the pump on the 41a from the sea cock, then to the oil cooler which is under the heat exchanger, then from the oil cooler to the intercooler, back across the rear of the engine to the gearbox (if you have volvos MS4) then to the heat exchanger through that to the exhaust elbow, all done from memory so dont quote me 100% but that gives the general route.

Aquastar may have done there own route from the seacock to the gearbox oil cooler but only if they didnt use the volvo box, which they may have used a hurth which has a non volvo cooler.

Hope that helps, im also in Port Solent and the area most weeks if your boats near.

The exhaust flap was a real pain as it rusted in place if the boat was left and not run for a while which then caused smoking under load, it was only fitted on the 41a prefix, dropped when the 41b was introduced as better pumps and injectors were designed with different injection angle and settings, along with different piston design and compression ratio.

Ive lost count how many flaps ive lockwired open over the years, the solenoids are unreliable and very costly.

 

[scottie]

From past experience there is no point taking these injectors to any other than best diesel shop and even then I would consider replacement units
I have seen too much spent on 41s when the injectors were checked on out of date test equip
The workshop books on these units as I recall we're decided into individual sections which made them pricey
As all ways take usual precautions and use correct tool when removing injectors

Were the P engines not the pleasure higher rated engines.

At one time ther was a DIY book for these units

 

[volvopaul]

From past experience there is no point taking these injectors to any other than best diesel shop and even then I would consider replacement units
I have seen too much spent on 41s when the injectors were checked on out of date test equip
The workshop books on these units as I recall we're decided into individual sections which made them pricey
As all ways take usual precautions and use correct tool when removing injectors

Were the P engines not the pleasure higher rated engines.

At one time ther was a DIY book for these units

The 41P was the last of the run with most of the right internals giving 200hp ( give or take)

 

[boatmike]

Hi mike, the raw water circuit which does cooler the aftercooler is fed from the sea water pump, water enters the pump on the 41a from the sea cock, then to the oil cooler which is under the heat exchanger, then from the oil cooler to the intercooler, back across the rear of the engine to the gearbox (if you have volvos MS4) then to the heat exchanger through that to the exhaust elbow, all done from memory so dont quote me 100% but that gives the general route.

Aquastar may have done there own route from the seacock to the gearbox oil cooler but only if they didnt use the volvo box, which they may have used a hurth which has a non volvo cooler.

Hope that helps, im also in Port Solent and the area most weeks if your boats near.

The exhaust flap was a real pain as it rusted in place if the boat was left and not run for a while which then caused smoking under load, it was only fitted on the 41a prefix, dropped when the 41b was introduced as better pumps and injectors were designed with different injection angle and settings, along with different piston design and compression ratio.

Ive lost count how many flaps ive lockwired open over the years, the solenoids are unreliable and very costly.

Interesting Paul, thanks. Now clear I think. Actually the solenoid on one engine was working and the other not but by tracing the wiring back to the actuating relay I found why and fixed it. both now work OK so I guess I will leave it. I do recognise though that it's not essential to normal running so if they go belly up no problem so long as it's belly up open not belly up closed! I now understand the circuit as you describe it but terminology still baffles. We seem to be calling it an intercooler one minute, an aftercooler the next and then using this term Charge Air Cooler I have never heard used before that started my question in the first place. Am I right that the turbo compresses air, forces it through the "intercooler" and then to the inlet manifold? Thus the term "aftercooler" means after the turbo but "intercooler" means between turbo and inlet making it a CAC so same difference? If so I understand. Regardless of terminology though unless there is a leak of either air or water what "maintenance" is necessary?

 

[volvopaul]

Interesting Paul, thanks. Now clear I think. Actually the solenoid on one engine was working and the other not but by tracing the wiring back to the actuating relay I found why and fixed it. both now work OK so I guess I will leave it. I do recognise though that it's not essential to normal running so if they go belly up no problem so long as it's belly up open not belly up closed! I now understand the circuit as you describe it but terminology still baffles. We seem to be calling it an intercooler one minute, an aftercooler the next and then using this term Charge Air Cooler I have never heard used before that started my question in the first place. Am I right that the turbo compresses air, forces it through the "intercooler" and then to the inlet manifold? Thus the term "aftercooler" means after the turbo but "intercooler" means between turbo and inlet making it a CAC so same difference? If so I understand. Regardless of terminology though unless there is a leak of either air or water what "maintenance" is necessary?

Yes all the same, cac int aft etc. Engineer language.

Maintinance, yes for sure a full strip down clean inside and out, new top gaskets, clean housing etc, and a mandatory pressure test before you fit it!

 

[boatmike]

Yes all the same, cac int aft etc. Engineer language.

Maintinance, yes for sure a full strip down clean inside and out, new top gaskets, clean housing etc, and a mandatory pressure test before you fit it!

OK, as I thought then. Thanks. All the confusion was basically because I am familiar with land based diesels which obviously don't have salt water cooling systems. Intercooler yes, in some but not all instances and arranged somewhat differently. Marine experience so far limited to naturaly aspirated diesels up to 60HP so it's all a welcome learning curve and again the forum is proving useful. Ta!